In almost every TV sitcom, feel-good childhood flick, and youth novel there is the token “fat kid." Think about it. In the wholesome 1950s family show Leave it to Beaver, it was Robert "Rusty" Stevens, the Beaver’s slovenly friend who constantly cut sports and over-ate leftovers. In the 1985 film The Goonies, it was the loveable Chunk, who even in the face of imminent danger would daydream about food. More recently, the “fat” role was somewhat demonized in the Harry Potter series with the main character's lazy, spoiled cousin Dudley. Such characters aside, though, having or being an overweight child is no laughing matter.

Officially, obesity in children is defined as a body fat level that is over 30 percent for girls and 25 percent for boys. Unlike adults, children are measured on the Body Mass Index (BMI) scale according to their age and gender, as their height is frequently changing. For children between two and 19 years-old, Centers for Disease Control Growth Charts define those with a BMI at or above the 85th percentile and below the 95th percentile for children of the same age and sex as overweight; those with a BMI at or above the 95th percentile are classified as obese.

But BMI isn’t the only way to determine whether or not a child is obese.

“BMI is best used as a screening tool to determine if a child over the age of two is underweight, healthy weight, overweight, or obese,” explains Deborah Orlick Levy, M.S., R.D., and Carrington Farms health and nutrition consultant. “Depending on the results, further diagnostic testing may be required. In order to have an accurate assessment, a health care provider would need to use other techniques, such as triceps skinfold measurements, full nutritional assessment, family history, activity records, and other quantifiable medical data.”

The “cost” of childhood obesity isn’t just unhappy children. Among other things, according to the CDC, “Obese youth are more likely to have risk factors for cardiovascular disease, such as high cholesterol or high blood pressure. In a population-based sample of five- to 17-year-olds, 70 percent of obese youth had at least one risk factor for cardiovascular disease.”

The CDCalso reports that children who are obese are likely to grow up to be obese adults and are at risk for issues like heart disease, Type 2 diabetes, stroke, several types of cancer, and osteo-arthritis. Beyond that, studies indicate that “the direct and indirect costs of obesity are more than $190 billion annually and preventing as few as five percent of new cases of chronic conditions, including obesity and related complications, would reduce Medicare and Medicaid spending by nearly $5.5 billion a year by 2030.” There are also reports that indicate that by 2030, half of all adults (115 million adults) in the United States will be obese.

The times, they are a changin’, however. Recently, the New York Times reported that obesity rates for children between two and five years of age have plummeted 43 percent in the last decade. The same study further claims that it appears that the obesity “epidemic” may be over, with Americans showing no drastic increase in obesity overall since 2003.

“Lack of awareness in the past few years has contributed to obesity rates,” explains certified nutritionist Deborah Enos. “There is so much wonderful nutritional information available now — and increased internet access for low-income Americans — and that has led to the drop in obesity rates. We haven’t seen the same in the older groups because that age group is very hard to reach with high levels of influence among group members.”

For some, the term “epidemic,” when applied to childhood obesity, was vastly misused in the first place. Paul Campos, who authored the controversial book The Obesity Myth: Why America’s Obsession with Weight is Hazardous to Your Health, has publicly criticized our perception of obesity and weight. In an interview with the Boston University School of Public Health, he stated that the decline in obesity rates was basically an indication of, well, nothing.“Obese youth are more likely to have risk factors for cardiovascular disease, such as high cholesterol or high blood pressure. In a population-based sample of five- to 17-year-olds, 70 percent of obese youth had at least one risk factor for cardiovascular disease,” according to the CDC.

“Like most of these reports that come out about weight, I think it’s important to contextualize,” Campos said. “Obesity among preschoolers, as an indicator, was just invented a few years ago by the CDC — not based in science, but just an arbitrary definition. Basically, they took the 95th percentile of the height-weight chart from the 1960s and 1970s and treated that as a definition of childhood obesity. So it’s kind of a made-up definition. And I have trouble seeing a decline in a made-up definition as a big deal.”

Needless to say, not everyone shares his view.

“Think about it," says Enos. “How many overweight kids were in your classes in elementary school? Maybe one or two? How about today? I see about 10 to 20 percent of kids in elementary school that are well above a healthy weight for their age group. Do I call it an epidemic? If not an epidemic, it certainly is a very disturbing trend.”

Marion Nestle, Paulette Goddard Professor in the Department of Nutrition, Food Studies, and Public Health at New York University, believes that the facts speak for itself.

“This depends on how you define epidemic. The word is convenient to use as a more attention-getting description of the increasing prevalence. This is a question of word choice. The basic fact is that obesity among children ages 2 – 19 has tripled since 1980.”

It isn’t easy to pin down exactly what caused this, well, trend. For Deborah Levy, the answer is twofold.

“First, these kids are less active,” she explains. “Years ago, kids would ride bikes to go to friends' houses; today they are driven everywhere. Kids also used to have a gym class at school almost every day of the week. Now, gym classes are only a couple of days a week. Our tweens and teens spend more time on the computer, cell phone, playing hand-held games, and watching TV than playing ball or jumping rope outside. Next, portion sizes of the foods kids choose to eat often are growing in size. For example, bagels are twice the size of what they used to be and pizza slices are much larger as well. So, when kids don’t realize what portion sizes should be and think they can enjoy a bagel or two slices of pizza, what they don’t realize is they may be taking in the equivalent of two bagels or four slices of pizza in calorie and fat content.”